Influence of the gravitational lunisolar torque on the atmospheric angular momentum budget.

International audienceAtmospheric effects on the Earth rotation are usually estimated by assuming that the Earth atmosphere system is isolated. Hence, any change in the atmospheric angular momentum (AAM) is totally governed by the interaction torque between the solid Earth and the atmosphere, and is considered to be fully transmitted to that of the solid Earth. This would no more be the case if external forces were perturbing this system. The role of the gravitational lunisolar force on the AAM budget is investigated by computing the associated torque. A non negligible contribution is found at several diurnal frequencies emphazing the necessity of taking this effect into account. The consequences on the Earth rotation theory are given